Family: Poaceae |
M.J. Harvey and Mary E. Barkworth Plants perennial; cespitose, sometimes also rhizomatous. Culms 5–90 cm, erect or decumbent at the base. Leaves basally concentrated; sheaths open to the base, smooth, glabrous; auricles absent; ligules memb, scabridulous dorsally, truncate to subacute, entire to lacerate; blades flat, folded or involute. Inflorescencespanicles, exserted at maturity, not disarticulating; branches ascending to erect or appressed. Spikeletspedicellate, weakly laterally compressed, with 1 floret; rachilla usually prolonged 0.1–1.9 mm beyond the base of the floret, sometimes absent, especially from the lower spikelts within a panicle, apices glabrous or with hairs, hairs to 0.3 mm; disarticulation above the glums, beneath the floret. Glumes equal or the lower glume longer than the upper, flexible, acute to acuminate, soometimes apiculate, unawned; calluses glabrous or hairy, hairs to 0.5 mm; lemmas membranous, (3)5-veined, veins mostly obscure, somtimes prominent distally, apices truncate to rounded or acute, unawned or awned, awns to about 1.3 mm, usually subapical, occasionally attached near midlength; paleas more than 1/2 as long as the lemmas, 2-veined, thinner than the lemmas; anthers 3. Caryopses shorter than the lemmas, concealed at maturity. x = 7. Name from the Greek pous, ‘foot’, and the genus Agrostis. Podagrostis is a genus of six or more species that grow in cool, wet areas. In the past, its species have been included in Agrostis. Three species grow in North America north of Mexico. Podagrostis differs from Agrostis in its combination of a relatively long palea and, usually, the prolongation of the rachilla beyond the base of the floret. It differs from Calamagrostis in the poorly developed callus hairs and awns. This treatment differs from the treatment in the FNA volumes and the Manual in recognizing P. thurberiana as distinct from P. humilis, a decision based on consideration of Arnow (1987) and additional examination of specimens. |